1. Field of the Invention
The present invention relates to a liquid crystal display and a thin film transistor array panel.
2. Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes two panels provided with field-generating electrodes, and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer, which determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
The LCD has a disadvantage of a narrow viewing angle. Various techniques for enlarging the viewing angle have been suggested, and a technique utilizing a vertically aligned LC and providing cutouts or protrusions at field-generating electrodes such as pixel electrodes and a common electrode is promising.
To describe the method of providing cutouts in more detail, pixel electrodes and a common electrode respectively have cutouts, the cutouts induce a slanted electric field, and the slanted electric field controls falling directions of liquid crystals. Control of the falling direction of liquid crystals makes it possible to widen the viewing angle of liquid crystal display. To describe the method of providing protrusions in more detail, protrusions are formed on both of pixel electrodes and a common electrode, the protrusions induce a slanted electric field, and the slanted electric field controls falling directions of liquid crystals.
Other methods in which pixel electrodes have cutouts and protrusions formed on a common electrode is also possible to control falling directions of liquid crystals. An LCD using cutouts or protrusions has an excellent viewing angle of over 80 degrees in any direction, in view of the contrast ratio where 1:10 is a standard contrast ratio and in view of gray scale inversion where a viewing angle of occurring brightness inversion is a standard angle. However, such an LCD shows poor visibility that is even inferior to a twisted nematic mode LCD. The poor visibility is caused by discordance of the gamma curve between the front view and side view. For example, in a vertically aligned mode LCD using cutouts, as the viewing angle is increased, the picture plane becomes brighter and the color shifts toward white. When this phenomenon is excessive, the image is distorted because the brightness difference between gray scales disappears. As the use of the LCD is widened to include multimedia displays, the visibility becomes more important.